The magnitude 8.1 earthquake occurred off the Pacific coast of Mexico. The damage
was concentrated in a 25 square km area of Mexico City, 350 km from the epicenter.
The underlying geology and geologic history of Mexico City contributed to this unusual
concentration of damage at a distance from the epicenter. Of a population of 18 million,
an estimated 10,000 people were killed, and 50,000 were injured.